In a typical wireless network utilizing a coordination function for coordinating transmissions among wireless stations, such a function may be implemented in one of the wireless stations or a coordinator device such as an access point (AP). The wireless stations may be consumer electronics (CE) devices which communicate via directional transmissions using sector antennas and beam forming antenna arrays. The coordinator device may use omnidirectional transmissions for broadcasts to all wireless stations in all directions (e.g., 360 degrees range). Alternatively, the coordinator may use quasi-omnidirectional transmissions for broadcasts to a wide range, but not necessarily in all directions.
In many wireless area networks (WLAN) and wireless personal area network (WPAN) standards, a coordinator station in infrastructure mode is used for providing contention free access to a wireless communication medium to support Quality of Service (QoS) for certain applications such as audio/video (A/V) applications (e.g., multimedia audio and video applications). Many WLAN/WPAN standards such as IEEE 802.11, IEEE 802.15.3, WirelessHD and WiGig, support or fully operate in infrastructure mode, in which a centralized coordinator or access point (AP) is used to control and manage the wireless network.
In the absence of a coordinator, to provide contention-free channel time reservation, existing techniques use announcement or information exchange among wireless stations in a network to negotiate/reserve the use of the communication medium. Specifically, QoS support for A/V applications is achieved using announcement or information exchange according to the IEEE 802.11e Enhanced Distributed Channel Access (EDCA), and the ECMA 368 specifications. EDCA defines four Access Categories (ACs) and introduces service differentiation such that A/V data traffic uses higher priority parameters to contend for the communication medium. However, EDCA does not provide collision free QoS services and bandwidth suffers under high contention. Further, ECMA 368 specification utilizes a multi-band OFDM alliance (MBOA) media access control (MAC) layer with a distributed scheduling protocol to provide communication medium reservation for contention free access. However, MBOA MAC uses a complex multi-beacon mechanism that is inefficient and difficult to manage, especially for 60 GHz wireless networks where most transmissions are not omnidirectional.
Further, in many WLAN and WPAN communication standards that utilize channel time reservation either in a centralized or a distributed manner, legacy wireless stations use contention-based wireless medium access and are unaware of channel time reservation schemes. These legacy wireless stations may contend and occupy channel time which jeopardizes the channel time reservation operations of non-legacy wireless stations.